Traditionally, aircraft electronics systems provide for and control the power needs of various essential aircraft functions, as well as passenger infotainment systems, automated seat functions, lights, and other equipment that are controlled either by aircraft crew or by passengers. To enable various control functions, such electronic systems generally provide for communications based on a specific communications protocol over an associated bus structure distributed throughout the aircraft that connects various aircraft components. For example, historical, the RS-485 serial communications protocol has been a widely-used communications protocol in many passenger aircraft.
The RS-485 protocol is a low speed communications protocol that operates over a two wire bus (a balanced twisted pair) in a star topology. However, while the RS-485 protocol has found wide-spread use in many narrow body aircraft, its relatively low speed does not permit it to operate effectively over the larger distances found in many wide body aircraft. Such larger aircraft generally have a greater number and wider array of devices that need to electronically communicate across larger distances with each other and with the central electronics in the aircraft. For this purpose, faster protocols have been developed that can still communicate over a twisted pair two wire bus.
In particular, a communications protocol that operates in accordance with the emerging 802.3bw Standard provides a higher speed 100 BASE-T1 Ethernet communications protocol (100 Mb/s) over a single balanced twisted wire pair bus. Its higher speed and ability to operate over the same two wire bus, makes it more desirable for use in certain aircraft (e.g., wide body aircraft) than the older and slower RS-485 protocol.
With the emerging use of the 802.3bw Standard in aircraft, it has become desirous for electronics systems suppliers to the avionic industry to provide a universal electronics box that permits, for example, an aircraft manufacturer to readily select either the RS-485 or 802.3bw communications protocol for use in a particular aircraft, based on determinations made by the aircraft manufacturer and customer.
Significantly, in accordance with this disclosure, a universal electronics box that provides for selection between two communications protocols (e.g., RS-485 or 802bw) is configured in a space and resource efficient design. As disclosed herein, in certain embodiments such universal electronics box does not require any additional connector pins or additional relays, as compared to prior art systems designed for use with only the RS-485 protocol. Since aircraft connectors generally tend to be expensive components and space for additional connectors is limited, providing such selection capability while keeping the same number of pins not only results in cost savings, but also permits additional functionality to be included in the same footprint as prior designs.
Interface configurations are further disclosed herein for electronic systems that permit selection from among multiple communications protocols across multiple ports in a space efficient design that keeps additional connector pins to a minimum.